Vacuum-tube circuits



May 6, 1.924.. 1,493,217

R. c. MATHES VACUUMf TUBE CIRCUITS Original Filed Oct." 23. 1916 QPatented May 6, 1924.

N TE STA 1,493,217 rss PATENT orncl-z.

aonnn'rc. MATHES, on NEW Yonx, it. Y., assrenon 'ro wnsrnnir nnncrmc cou- -ra w, on NEW YORK, N. 2;, a conrona'rxon on NEW YORK,

VACUUM-TUBE cracurrs.

- Original application filed October 23, 1916, Serial No. 127,120}. Patent No. 1,426,754, dated. August 22,

1922. Divided and this application filed October 17, 1819. Serial No. 881,468.

To all whom it'mag concern:

Be it known that I, ROBERT C. Mamas, a citizen of the United States, residing atNew York, in the county of Bronx, State of New 6 York, have invented certain new and useful Improvements in Vacuum-Tube Circuits, of which the following is a full,clear, concise, and exact description.

- Thisinvention relates to sources of direct current potential for the-input circuit of a vacuum tube of the electron dischargetype.

.Its ob'ect is to provide a more convenient and deslrable method than has heretoforebeen used-for securing a desired difierence of potential between the, filamentan'd the gri of a vacuum tube.

further object is to. furnish a means .for securing deslred differences of potential between the respective grids and filaments in circuits in which a plurality of electron discharge devices are employed.

In the herein a source of current separate from the sourcesof heating current and space cur- 26 rents is employed, and the; input electrodes of the vacuum tubes are connected to suit-, able taps on an impedance adapted to be -.traversed by current from this separate source. This ap lication is a division of application Sena No. 1274201}, filed October 23, 1916, patented August 22, 1922, No.

1,426,754.- a a Y These and otherobjects of the invention will be more fully unde'rstood from the fol-' lowing detailed description taken in connection with the accompanying drawing in which the view represents diagrammatically I a circuit embodying the invention.

4 Referring tothe-drawing by reference numerals, the vacuum tube 1 contains the grid or control electrode 2, the filamentary oath: ode 3, and the anode 4. The vacuum tube 1 is similar and contains corresponding electrodes 2', 3' 'and 4'. Space .current is supplied to the tubes by source 5. The cath odes 3 and 3 are connected in series with a source of heating current 6. The desired i .difierence of potential between the grid and- 1 150 cathodeofthe respective tubes is obtained from a-source'of potential 7 which supplies current to the 'res1stances15,'9 and 9. The 5 drop potential in resistance 9'. is supplied 5 embodiment of the invention shown to the input circuit of tube 1, and the drop in potential in resistances '9 and 9. is supplied to the input circuit of tube 1. Thevalues of these potential difierences can be varied by changing the values of the respective resistancesv or of resistance 15.

The output circuit of tube 1 comprises inductan'ce 11 in the direct current path,- and condenser 12 and potentiometer resistance 26 in the alternating current portion of the circuit. The output circuit of tube 1 comprises inductance 11 and condenser 12,

put transformer 13.

similar to the correspondingelements in the preceding circuit, and theprimary' of out- A choke coil 14 is placed in series with batte 6 to prevent fluctuations of the battery om affecting the operation of the tubes. For similar reasons seriesinductances 16 and shunt condenser 18 are placed in. circuit with battery 7 and series inductance 21 and shunt condenser 20 in circuit w1thbattery 5. In case sources 5 and 7 are storage batteries, they may be charged by connecting the generator 19 in circuit therewith.

Condensers 17 and 17 are to resistance 9 and 9' to provi e an easy path for alternatin currents. These condensers glaced' in shunt are particular y useful in minimizing cross- In operation signaling currents from the line 23 flow through resistances 24 and 25,

talk in case more than one amplifier of this type is operated from' a common battery. I

these resistances bein so proportioned that a desired amount of t e potential drop therethrough will be impressed on the input electrodes of tube "1. -The amplified current from tube 1 is impressed'through, potenti- .ometer 26 on the input electrodes of tube 1 and the ream lified current is transmitted through transibrnier 13 to .a suitable line" or other electricaldevice,,n0t shown.

The arrangementwhereby the output voltages of one tube are impressed on the input electrodes of another'tubewill be referred to in the claims as atandem arran ement.

It will be noted thatthe batteries are. of the same type and will therefore be subjected to the" same sort of fluctuations. If, for example, these batteries are they will gradually drop ,in volta dry cells, e as they are used, and a gradual drop e voltage and5 - stantially constant. v

storage batteries, there will be a gradual vention is not limited to the exact form shown but it entitled to equivalents within of the output battery will be compensated for by a similar drop in'the input battery.

For example, if the anode becomes more positive the grid will become more negative and thus maintain 'the space curren t sub- If these batteries are the scope of the appended claims.

What is claimed is: w Y V l.- In combination, a plurality of electron discharge devices each having an input termin a1, a source of potential, a plurality of taps of difi'erent potentials at points in series on said source, and a connection from each of said input terminals to one of said taps.

2. discharge devices each having an input terminal, said devices being arranged in tandem, a source of potential, a plurality oftaps of difierent potentials at points in series on said source, and a connection from each of said input terminals to one of said taps.

3. In combination, a lurality of electron discharge devices, each aving an-input terminal, a source of current, an impedance in circuit with said source, a plurality o l taps at points. in series on saidimpedance, and connections from said taps to said input terminals. I I

4 In dombination, a pluralityof electron discharge devices each having a cathode and a control electrode, a source of current, an 1mpedance adapted to be traversed by current from said source, and connections from points in series on said impedance to said cathedes and control electrodes.

5. In combination, a plurality 0f electron d1SCl1aI'g'edoV1CeS each having a cathode and a control electrode, asource of current, an

impedance adaptedto be traversed by current from said source, said cathodes being connected to the more positive end of said impedance, and said control electrodes being points in series on said im- 6.1m combination, an electron disc'har device havingia control electrode, a catho e,

and a cathode heating circuit, a source of current, and an'impedance 1n clrcuit w1th said source, said heating circuit being connected to one end of said impedance, and said control electrode being connected to a point intermediate the ends of said imneaaiv rent from said source, connections from both ends of said cathode to the more pos1- tive end of said impedance and a connection from said control electrode to a point intermediate the ends of said impedance, said control electrode being thereby maintained more negative that any part of said cathode.

8. In combination, a plurality of electron discharge devices, each having an input terminal, a source of current, aniimpedanoe n circuit with said source, a plurahty of nected between each two adjacent-taps, and

a connection from each out said input ter=- minalis to a tap on said impedance. 9. n

.. taps on said impedance, a condenser concombination, a plurality'of electron discharge devices each having a cathode and' a control electrode, a source of potential, a plurality of taps of difi'erent potential at v v points in series on said source, a connection In combination, a plurality of electron from each of said centrol electrodes to one of said taps, said cathodes being connected 10. lln combination, a plurality of electron discharge devices each having a cathode and a control electrode, a source of potential, at plurality'of taps of difierent potential at points in series on said squrce, a connection from each of said control electrodes to one of said taps, said cathodes being connected to the positive endof said source, each of said control electrodes being thereby nor mally maintained more negative than any part of the corresponding cathode.

11. lln'combination, a plurality of electron discharge devices each having a cathode ,and

a control electrode, means for passing heat- 7 ing current serially through said cathode, a source of potential, a plurality of taps of difi'erent potential at points in series on said source, aconnection from each (if said 1 control electrodes to one of said taps,said

cathodes being connected to the positive end of said source, each of said control electrodes p being ctherelby, normally maintained more negative than any part of the corresponding cathode. A

12. In combination, a plurality of'electron discharge devices each having a cathode and a control electrode, a source of current, an impedance adapted to be traversed by current from said source, said cathodes being connected to the more positive end of said impedance, and said control electrodesbeing connected to points in series on said impedance, and capacities providing paths of low impedance to alternating current, connecting said points to said end of said impedance.

13. In combination, a plurality of electron discharge devices each having a cathode and control electrode, a source of current, an impedance adapted to be, traversed by current from said source, connections from points in series on said impedance to said cathodes and control electrodes, and capacities providing paths of low impedance to alternating current, connected across said connections.

14. In combination, a plurality of electron discharge devices each having an input termmal, a source of potential, a plurality of taps of different potentials at points in series on said source, a connection from each 1 my name this 14th day of October, A. D. 25

ROBERT C. MATHESI 

